Writing instrument



Oct. 17, 1961 w. H. KERSTEN El'AL 3,

WRITING INSTRUMENT Filed July 5, 1955 Q Q Q Q Q Q Q Q Q Q Q i d Q... lh

3,004,520 WRITING INSTRUMENT William H. Kersten, Janesville, and Roger Polan, Milton,

WIS. assignors to The Parker Pen Company, Janesville, Wis., a corporation of Wisconsin Filed July 5, 1955, Ser. No. 519,743 3 laims. (Cl. 120--42.03)

The present invention relates to writing instruments and more particularly to retractable writing instruments.

A retractable writing instrument of the general character herein considered includes a barrel or holder and a writing unit having a writing point mounted in the holder for movement between a retracted position in which the writing point is concealed within the barrel and a projected position in which the writing point is projected forwardly beyond the barrel in position for writing.

An object of the invention is to provide a writing instrument of the foregoing general character having novel construction and combination of means for projecting the writing unit and retaining it in projected position.-

A further object is to provide a retractable writing instrument having push button means for projecting the writing unit and means for releasably retaining the unit in projected position reactive to the characteristics of the manner of projecting the unit whereby the user may sense by the feel of the push button the tightness 'with which the unit is being held in projected position.

A more specific object is to provide a retractable writing instrument having push button means for projecting the writing unit and means for releasably retaining the unit in projected position including tapered elements on the barrel and unit which are brought into wedging engagement in response to depression of the push button, whereby the user may sense by the feel of the push but- {ton the extent of gripping action exerted on the unit.

A still further object is to provide a writing instrument of the foregoing general character with alternative arrangement for projecting the writing unit.

Other objects and advantages will appear from the following detail description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a writing instrument embodying the principles of the present invention, showing the writing unit in projected position; and

FIG. 2 is a view similar to FIG. 1 but with the writing unit in retracted position.

The instrument illustrated in the drawings as embodying the principles of the invention is a ball point pen. Although the invention is illustrated as embodied in a ball point pen, it will be understood that it is not limited thereto, but may be adapted to other writing instruments.

Referring in detail to the drawings, the writing instrument or ball point pen includes a barrel or housing 12 made up of a front point section 14 and a rear barrellike section 16 secured together in a suitable manner such as by screw threads 18. These elements may be of desired material, such as metal or plastic.

Mounted in the barrel is a writing unit 20 for movement between a projected position of FIG. 1 and a retracted position of FIG. 2. The writing unit 20, as in a ball point pen, includes a reservoir 22 containing the main body of ink or writing material and a stem portion 24 leading forwardly from the reservoir. In the present instance it is preferred that the reservoir 22 be of substantial diameter while the stem 24 is of a somewhat reduced diameter. The stem serves to convey the writing material from the reservoir to the writing point which is constituted by a ball 26 mounted in the forward end of the stem. Details of the interior of the writing unit and ttes Patent j 2 3,004,520 l Patented Oct. 17, 1961 of the writing ball and its mounting are not of the essence of the present invention.

Mounted in the rear end of the casing of the reservoir 22 is a push button 28 of suitable material such as plastic, it being secured therein in any suitable manner such as by a press fit. At the lower or inner end of the push button is a flange 30 which may be integral with the push button proper. Provision is made for venting the interior of the reservoir which may be done by means of an aperture through the push button or other suitable location. The writing unit has guided movement in the housing at spaced points, preferably adjacent the ends of the instrument. The forward end of the point section 14 is provided with a bore 3-2 for slidingly receiving the stem 24 while the flange 30 slidingly engages the inner surface of the rear barrel section 16. The engagement of these locations is such as to prevent undue side play of the writing unit in the barrel while enabling free sliding movement of it in longitudinal directions. A spring 34 surrounds the reservoir 22 and is compressed between the flange 30 and a shoulder at the forward end formed by a ring 36 fitted to the inner or rear end of the front point section 14. The spring acts against the flange 30 to bias the writing unit rearwardly toward retracted position, the writing unit in moving in that direction being limited by an inturned flange 38 which may be integral with the barrel section. The flange defines an opening receiving the push button 28.

The means for releasably retaining the writing unit in projected position includes wedging elements on the barrel and the unit, such that wedging engagement is established therebetween in response to forward projecting of the movement of the writing unit. These wedging elements take the form of a tapered portion 40 on the forward end of the resevoir 22 and a complementary tapered surface 42 formed in the barrel and specifically in the front point section 14. These tapered surfaces are of appropriate slope such that a secure wedging engagement is established for retaining the writing unit in projected position against normal pressures encountered in writing. The unit may be moved to projected position in either of two ways and this is an important feature in the invention. The user may apply his finger to the push button 28 and manually move the writing unit to projected position. He may also project the unit by means of inertia, as will be referred to again hereinafter. The unit and barrel are so relatively dimensioned that when the wedging action takes place, the push button remains slightly extended beyond the rear end of the barrel. The user is enabled to judge the feel of the unit in the Wedging action and thus control the degree of tightness with which the unit is wedged in projected position.

The writing unit acts against the retracting spring 34. In projecting the unit by depressing the push button, the force of the spring is readily overcome, but the spring must yield also when the unit is projected by inertia. Thus the user may grasp the instrument with the unit in retracted position, shake or jar the instrument forwardly, whereupon the inertia of the unit carries it forwardly against the action of the spring with such force as to cause the wedging and gripping action between the tapered surfaces 40 and 42.

Thus the instrument is of such character that it can be projected alternatively by depressing the push button or shaking the pen. In projecting by means of the push button the user can, by the feel of the wedging action, accurately judge the tightness with which the unit is wedged. Similarly, in projecting by inertia of the unit, the user can, to an extent, also by the feel of the instrument, judge and control the tightness with which the unit is wedged. i

Regardless of the manner in which the writing unit is projected, it is wedged and held in projected position sufficiently securely that it will not be retracted under the influence of ordinary writing pressures exerted on the point. In writing, the user normally holds the instrument at quite an angle to the vertical and the pressure on the point is not imposed directly longitudinally. For retracting the unit the user moves the pencil to a vertical or nearverticalposition and. imposes added or excessive pressure on the point. This pressure is imposed directly longitudinally and easily effects disengagement of the tapered surfaces whereupon the spring 34 moves the writing unit to retracted position.

In retracted position the writing point is entirely concealed within the barrel. The writing unit is so dimensioned that the push button remains extended beyond the rear end of the barrel even in projected position of the unit. The user thus may impose great or little pressure on the writing unit, to the extent desired by the individual so that the wedging effect may be correspondingly determined, as some people write with a heavier hand than others. Thus there is provided in the present construction possibility of a greater range of wedging effect to accommodate individual users.

We claim:

1. A retractable writing instrument comprising a barrel, a writing unit mounted in the barrel for movement between a retracted position and a projected position, spring means biasing the unit toward retracted position for retracting and retaining retracted the unit, the unit including, a push button extending from the rear end of the barrel for depression by the user for projecting the unit to projected position, and means for releasably retaining the unit in projected position consisting solely of an interengageable pair of forwardly converging tapered elements on the barrel and unit respectively capable of retaining the .unit in projected position against normal writing pressures but releasable in response to excessive pressure applied to the unit in rearward direction, said spring means and said unit being the only moving parts of the instrument.

ing retracted the unit, and means for releasably retaining the unit in projected position consisting solely of a pair of forwardly converging tapered elements on the unit 'and barrel respectively for wedging interengagement, the

parts being arranged so that the user may depress the pushbutton and thereby project the unit and the taper of the tapered elements being such as to enable the user to wedge the elements to diflerent degrees of tightness by depressing the push button, and the tapered elements being capable of being wedged so as to withstand normal pressures on the writing point encountered in writing but releasable in response to excessive pressure thereon when the instrument is in substantially vertical position, said spring means and said unit being the only moving parts of the instrument.

3. The invention set forth in claim 1 wherein the spring means is yieldable under the influence of inertia of the writing unit in response to shaking the instrument forwardly, whereby alternative arrangement is provided for projecting the unit by either manually depressing the push button or shaking the pen in the manner stated.

References Cited in the file of this patent UNITED STATES PATENTS 362,121 Spear May 3, 1887 2,591,655 Foley Apr. 1, 1952 2,593,366 'I'hull Apr. 15, 1952 2,676,569 Schrader Apr. 27, 1954 '2,773,478 Poinsot Dec. 11, 1956 2,776,646 Spatz Ian. 8, 1957 

